Nursing Elites

1. Which of the following organs is NOT directly involved in the mechanical breakdown of food?

• A. Mouth
• B. Stomach
• C. Small intestine
• D. Esophagus

Correct answer: D

Rationale: The correct answer is D, esophagus. The esophagus is a muscular tube that connects the mouth to the stomach, but it is not directly involved in the mechanical breakdown of food. The mouth is responsible for the initial mechanical breakdown of food through chewing, the stomach further breaks down food through muscular contractions, and the small intestine aids in the digestion process. However, the esophagus primarily serves to transport chewed food from the mouth to the stomach via peristaltic movements, without actively breaking down the food itself.

2. What is the process of converting DNA into a protein called?

• A. Transcription
• B. Translation
• C. Replication
• D. Mutation

Correct answer: A

Rationale: Transcription is the process of converting DNA into a molecule called messenger RNA (mRNA). This mRNA molecule carries the genetic information from DNA to the ribosomes, where it is used to make proteins.

3. Balance the following redox reaction in acidic solution: I⁻ (aq) + Cr₂O₇²⁻ (aq) -> I₂ (aq) + Cr³⁺ (aq). Identify the oxidizing agent and reducing agent.

• A. I⁻ is oxidized, Crâ‚‚O₇²⁻ is reduced
• B. I⁻ is reduced, Crâ‚‚O₇²⁻ is oxidized.
• C. Both I⁻ and Crâ‚‚O₇²⁻ are oxidized.
• D. Both I⁻ and Crâ‚‚O₇²⁻ are reduced.

Correct answer: A

Rationale: . I⁻ loses an electron (oxidation), Cr₂O₇²⁻ gains electrons (reduction).

4. The human eye focuses light by adjusting the shape of its:

• A. Cornea
• B. Iris
• C. Lens
• D. Retina

Correct answer: C

Rationale: The human eye focuses light by adjusting the shape of its lens. The cornea is the transparent outer covering of the eye that helps to focus light, but it does not change shape. The iris regulates the amount of light entering the eye through the pupil but does not adjust the shape of the light. The retina is the layer at the back of the eye that receives and processes light signals but does not play a role in focusing light. Therefore, the correct answer is C, the lens, as it changes shape to focus light onto the retina, allowing for clear vision.

5. Which of the following is the main organ responsible for producing antibodies?

• A. Thymus gland
• B. Spleen
• C. Bone marrow
• D. Lymph nodes

Correct answer: C

Rationale: Rationale: Antibodies are proteins produced by specialized white blood cells called B lymphocytes (B cells). These B cells mature in the bone marrow, where they undergo a process of differentiation and maturation to become plasma cells that secrete antibodies. The bone marrow is the primary site for the production of B cells and antibodies in the immune system. The thymus gland is responsible for the maturation of T lymphocytes (T cells), not antibody production. The spleen and lymph nodes play roles in filtering and trapping pathogens but are not the main organs responsible for producing antibodies.

6. Action potentials, the all-or-nothing electrical signals traveling along neurons, are generated by the movement of:

• A. Glucose
• B. Sodium and potassium ions
• C. Neurotransmitters
• D. Myelin

Correct answer: B

Rationale: The correct answer is B: Sodium and potassium ions. Action potentials are generated by the movement of sodium and potassium ions across the neuronal membrane. During depolarization, sodium ions rush into the cell, causing a change in electrical charge. This influx of positive ions triggers the opening of voltage-gated potassium channels, allowing potassium ions to exit the cell during repolarization. Glucose is a source of energy for cells but does not directly generate action potentials. Neurotransmitters are chemical messengers released at synapses, while myelin is a fatty substance that insulates axons, speeding up the conduction of action potentials but not directly generating them.

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